NAME
App::Multigit - Run commands on a bunch of git repositories without
having to deal with git subrepositories.
PACKAGE VARS
%BEHAVIOUR
This holds configuration set by options passed to the mg script itself.
Observe that mg [options] command [command-options] will pass options
to mg, and command-options to mg-command. It is those options that will
affect %BEHAVIOUR.
Scripts may also therefore change %BEHAVIOUR themselves, but it is
probably badly behaved to do so.
report_on_no_output
Defaults to true; this should be used by scripts to determine whether
to bother mentioning repositories that gave no output at all for the
given task. If you use App::Multigit::Repo::report, this will be
honoured by default.
Controlled by the MG_REPORT_ON_NO_OUTPUT environment variable.
ignore_stdout
ignore_stderr
These default to false, and will black-hole these streams wherever we
have control to do so.
Controlled by the MG_IGNORE_{STDOUT,STDERR} environment variables.
concurrent_processes
Number of processes to run in parallel. Defaults to 20.
Controlled by the MG_CONCURRENT_PROCESSES environment variable.
skip_readonly
Do nothing to repositories that have readonly = 1 set in .mgconfig.
Controlled by the MG_SKIP_READONLY environment variable.
@SELECTED_REPOS
If this is not empty, it should contain paths to repositories. Relative
paths will be determined relative to .
Instead of using the .mgconfig, the directories in here will be used as
the list of repositories on which to work.
Each repository's origin remote will be interrogated. If this exists in
the .mgconfig then it will be used as normal; otherwise, it will be
treated as though it had the default configuration.
FUNCTIONS
These are not currently exported.
mgconfig
Returns .mgconfig. This is a stub to be later configurable, but also to
stop me typoing it all the time.
mg_parent
Tries to find the closest directory with an mgconfig in it. Dies if
there is no mgconfig here. Optionally accepts the directory to start
with.
all_repositories
Returns a hashref of all repositories under mg_parent.
The keys are the repository directories relative to mg_parent, and the
values are the hashrefs from the config, if any.
selected_repositories
This returns the repository configuration as determined by
. Directories that exist in the main
config (all_repositories) will have their configuration honoured, but
unknown directories will have default configuration.
each($command)
For each configured repository, $command will be run. Each command is
run in a separate process which chdirs into the repository first.
It returns a convergent App::Multigit::Future that represents all
tasks. When this Future completes, all tasks are complete.
Subref form
The most useful form is the subref form. The subref must return a
Future; when this Future completes, that repository's operations are
done.
The convergent Future ($future below) completes when all component
Futures (the return value of then, below) have completed. Thus the
script blocks at the $future->get until all repositories have reported
completion.
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run(\&do_a_thing)
->then($repo->curry::run(\&do_another_thing))
;
});
my @results = $future->get;
See examples/mg-branch for a simple implementation of this.
The Future can complete with whatever you like, but be aware that run
returns a hash-shaped list; see the docs for run. This means it is
often useful for the very last thing in your subref to be a
transformation - something that extracts data from the %data hash and
turns it into a usefully-shaped list.
The example examples/mg-closes does this, whereas examples/mg-branch
uses report.
report in App::Multigit::Repo implements a sensible
directory-plus-output transformation for common usage.
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run(\&do_a_thing)
->then($repo->curry::run(\&do_another_thing))
->then($repo->curry::report)
;
});
The subref given to run is passed the %data hash from the previous
command. %data is pre-prepared with blank values, so you don't have to
check for definedness to avoid warnings, keeping your subrefs nice and
clean.
sub do_a_thing {
my ($repo_obj, %data) = @_;
...
}
Thus you can chain them in any order.
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run(\&do_another_thing)
->then($repo->curry::run(\&do_a_thing))
->then($repo->curry::report)
;
});
Observe also that the interface to run allows for the arrayref form as
well:
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run([qw/git checkout master/])
->then($repo->curry::run(\&do_another_thing))
;
});
A command may fail. In this case, the Future will fail, and if not
handled, the script will die - which is the default behaviour of
Future. You can use else to catch this and continue.
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run([qw{git rebase origin/master}])
->else([qw{git rebase --abort])
->then($repo->curry::report)
;
});
The failure is thrown in a manner that conforms to the expected Future
fail interface, i.e. there is an error message and an error code in
there. Following these is the %data hash that is consistent to all
invocations of run. That means that when you do else, you should be
aware that there will be two extra parameters at the start of the
argument list.
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run([qw{git rebase origin/master}])
->else(sub {
my ($message, $error, %data) = @_;
...
})
->then($repo->curry::report)
;
});
In the case that you don't care whether the command succeeds or fails,
you can use finally to catch the failure and pretend it wasn't actually
a failure.
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run([qw{git rebase origin/master}])
->finally($repo->curry::report)
;
});
Despite the name, finally does not have to be the final thing. Think
"finally" as in "try/catch/finally". In the following code, finally
simply returns the %data hash, because finally transforms a failure
into a success and discards the error information.
use curry;
my $future = App::Multigit::each(sub {
my $repo = shift;
$repo
->run([qw{git rebase origin/master}])
->finally(sub { @_ })
->then(\&carry_on_camping)
->then($repo->curry::report)
;
});
Arrayref form
In the arrayref form, the $command is passed directly to run in
App::Multigit::Repo. The Futures returned thus are collated and the
list of return values is thus collated.
Because run completes a Future with a hash-shaped list, the convergent
Future that each returns will be a useless list of all flattened
hashes. For this reason it is not actually very much use to do this -
but it is not completely useless, because all hashes are the same size:
my $future = App::Multigit::each([qw/git reset --hard HEAD/]);
my @result = $future->get;
my $natatime = List::MoreUtils::natatime(10, @result);
while (my %data = $natatime->()) {
say $data{stdout};
}
However, the %data hashes do not contain repository information; just
the output. It is expected that if repository information is required,
the closure form is used.
mg_each
This is the exported name of each
use App::Multigit qw/mg_each/;
init($workdir)
Scans $workdir for git directories and registers each in .mgconfig
base_branch
Returns the branch that the base repository is on -the repository that
contains the .mgconfig or equivalent.
The purpose of this is to switch the entire project onto a feature
branch; scripts can use this as the cue to work against a branch other
than master.
This will die if the base repository is not on a branch, because if
you've asked for it, giving you a default will more likely be a
hindrance than a help.
set_base_branch($branch)
Checks out the provided branch name on the parent repository. Beware of
using a branch name that already exists, because this will switch to
that branch if it does.
AUTHOR
Alastair McGowan-Douglas,
ACKNOWLEDGEMENTS
This module could have been a lot simpler but I wanted it to be a foray
into the world of Futures. Shout outs go to those cats in
irc.freenode.net#perl who basically architectured this for me.
tm604 (TEAM) - for actually understanding Future architecture, and not
being mad at me.
LeoNerd (PEVANS) - also for not being irritated by my inane questions
about IO::Async and Future.
BUGS
Please report bugs on the github repository
https://github.com/Altreus/App-Multigit.
LICENSE
Copyright 2015 Alastair McGowan-Douglas.
This program is free software; you can redistribute it and/or modify it
under the terms of the the Artistic License (2.0). You may obtain a
copy of the full license at:
http://www.perlfoundation.org/artistic_license_2_0